1. Field of the Invention
The present invention relates to surface finishing devices which are adapted to be mounted for rotation on a spindle. The invention relates more particularly to an improved form of rotary flap sanding device.
2. Description of the Prior Art
A known form of a rotary surface finishing device, commonly referred to as a flap sander, comprises an array of elongated, flexible, abrasive strips which extend in a generally radial direction from a peripheral surface of a cylindrically shaped housing body. The strips are spaced uniformly about the periphery and each is maintained in a radially extending attitude during rotation by an adjacent backing body of a resilient material. The backing body is typically a bristle brush, which is mounted in juxtaposed relationship with the strip for rotation therewith. In operation, the housing is mounted on a spindle; it is rotated about its longitudinal axis; and, the device and a surface of a workpiece being finished are relatively positioned for contacting the surface with the rotating abrasive strips. During rotation as well as upon contact with the workpiece surface, the strips are deflected in a circumferential direction which is opposite to the direction of rotation. Deflection is limited during rotation, during contact and after contact by the adjacent resilient body. The rotating abrasive strips, which are flexible and yield upon contact, provide a device which advantageously enables finishing of surfaces having various configurations. A tool with which this flap sanding device is used is disclosed in copending U.S. patent application Ser. No. 010,912 which is filed concurrently herewith and assigned to the assignee of this invention.
Continued usage results in wear of extending working segments of the abrasive strips. In order to replace the worn segments, each abrasive strip is formed as an elongated body, a principal segment of which is stored in the housing member. The elongated strips extend from the housing interior through a slot in the peripheral surface and an external strip end segment provides the working abrasive surface. The plurality of abrasive strips have been wound on a reel within the housing. A means is provided for partly unwinding the reel in order to advance replacement segments of the strips from the interior of the housing to replenish the worn segments. The sanding flap wheel can thus be utilized over an extended period of time before the strips themselves need be replaced. Heretofore, the means provided for advancing the elongated strips from the housing have been relatively complex and costly and have required the user to, at least partly, disassemble the housing or adjust a housing cover in order to effect replenishment.